Evaluate the following expression when $y = 9$ and $x = 9$. $4$ $y$ $^2 + 4$ $x$ $ - 4$
Answer: Substitute $9$ for ${y}$ and $9$ for ${x}$ $ = 4{(9)}^2 + 4{(9)} - 4 $ Remember order of operations. Evaluate the exponent before you multiply. $ = 4(81) + 4{(9)} - 4 $ $ = 324 + 36 - 4 $ $ = 356$